Just like people, different sharks have different levels of sociability. Some sharks who interact more with others will stay in groups, while more solitary sharks would rather drift off alone and camouflage themselves at the bottom.
Shark sociability was rated by how they chose to stay safe when they were less than a year old. Most juvenile sharks chose the "safety in numbers" route. Other less social sharks masked themselves with their surroundings.
The study was conducted at the Marine Biological Association of the UK in partnership with the University of Exeter on 10 groups of captive catsharks, with 10 individuals in each group placed in different tank habitats.
Some tanks were complex and mimicked the sharks' natural habitat with rocks and various coral and flora, while other tanks were minimal with only gravel at the bottom.
Researchers found that the social sharks remained in their groups even when placed in different environments, with varying numbers of individual sharks in each tank. The sharks that were observed to be loners, remained solitary or joined significantly smaller groups.
The results, they said, are similar to observing a group of 10 human adults socializing with each other at the office, nightclub or other settings. Some people will tend to flock to others easily. Still, some will remain shy and be mostly solitary.
"We define personality as a repeatable behavior across time and contexts. What is interesting is that these behaviors differ consistently among individuals. This study shows, for the first time, that individual sharks possess social personalities," said Professor Darren Croft from Exeter University.
Although the study was conducted on captive sharks, which enabled the researchers to control and manipulate the experiments in ways that would be impossible with wild sharks, they expect similar results would be found if they were to study sharks in their natural habitat across different species.
The study on the social behavior of sharks seems to reinforce the findings of another study that showed that some sharks are more aggressive and thrill-seeking, while others are more laid back and mellow.
The researchers believe that their study shows that sharks have different personalities, just like humans. The investigators are eager to further study how other animals evolved their own individual personality traits as well.
